This invention relates to a method for producing metal carbide grade powders suitable for isostatic compaction techniques which involves combining the binder metal powder with an esterified wax prior to mixing with metal carbide. By the mixing of the wax with the binder metal first, the undersirable oxidation of the binder metal is prevented. Also a minimum amount of wax is needed and as a result, disintegration of parts during the dewaxing cycle is prevented and a desirable carbon level in the product powder is maintained.
Tungsten carbide grade powders are used in isostatic compaction to form parts that are used in applications such as can forming tools and rolling mill tools.
In the production of carbide grade powders such as tungsten carbide powders containing cobalt, care must be taken that the binder metal (cobalt) is not oxidized. Excess oxygen results in loss of strength in densified parts made from these powders.
In formation of parts or articles by isostatic compaction, the powder is mixed with a wax which serves as a binder. When the green article is formed the binder is burned out of the article prior to sintering. If the wax content is too high, the article can disintegrate after burn out of the binder due to cracks or excessive voids in the microstructure of the article. Therefore care must be taken that the wax content is not too high.
A method for producing metal carbide grade powder in which there is a minimum of oxidation of the binder metal and in which a minimum amount of wax can be used so that the powder is suitable for formation of high strength parts by isostatic compaction, would be desirable.